To make a computer not constituting cloud computing execute processing related to service by using grid computing.

If a service server 4 constituting cloud computing receives a service request from a client, an environment setting unit 42 sets an environment of grid computing between the server and a computer 3. If a computer decision unit 48 refers to resource information of the computer 3 to decide the computer 3 for executing service processing, an execution indication unit 49 divides a service program and indicates each computer 3 decided as an execution destination to execute each service program. An execution result transmission unit 51 summarizes processing results collected from each computer 3 and returns the resultant to the client.